Unit tests have become unstable since STU3 refactoring

[johnstairs]

https://microsofthealthoss.visualstudio.com/FhirServer/_build/results?buildId=1317&view=ms.vss-test-web.build-test-results-tab&runId=1016450&resultId=100728&paneView=debug

Error message
System.Exception : Please call SetProvider before using methods on this class.

Stack trace

at Microsoft.Health.Fhir.Core.Models.ModelInfoProvider.EnsureProvider() in /home/vsts/work/1/s/src/Microsoft.Health.Fhir.Core/Models/ModelInfoProvider.cs:line 28 at Microsoft.Health.Fhir.Core.Models.ModelInfoProvider.EnsureValidResourceType(String resourceName, String parameterName) in /home/vsts/work/1/s/src/Microsoft.Health.Fhir.Core/Models/ModelInfoProvider.cs:line 64 at Microsoft.Health.Fhir.Core.Features.Search.SearchValues.ReferenceSearchValue..ctor(ReferenceKind referenceKind, Uri baseUri, String resourceType, String resourceId) in /home/vsts/work/1/s/src/Microsoft.Health.Fhir.Core/Features/Search/SearchValues/ReferenceSearchValue.cs:line 34 at Microsoft.Health.Fhir.Core.UnitTests.Features.Compartment.CompartmentIndexerTests.GivenSearchIndicesWithResourceTypeAndCompartmentType_WhenExtracted_ThenCorrectIndicesExtracted(ResourceType resourceType, CompartmentType compartmentType, String resourceId) in /home/vsts/work/1/s/src/Microsoft.Health.Fhir.Core.UnitTests/Features/Compartment/CompartmentIndexerTests.cs:line 39

[brendankowitz]

This looks stable now